1. Field of the Invention
This invention relates to vehicle suspensions and, in particular, to a front suspension for coupling a steer axle assembly to a vehicle frame.
2. Discussion of Related Art
A conventional vehicle includes a vehicle frame having a pair of longitudinally extending frame rails that support the vehicle engine and body. The frame is supported on a plurality of ground-engaging wheels that are disposed at opposite ends of a plurality of axles. The vehicle may contain, for example, a steer axle on which the wheels are steerable by the vehicle operator and a drive axle whose wheels are driven by the vehicle engine. Each of the axles are coupled to the vehicle frame through a suspension that dampens movements transmitted between the wheels and the vehicle frame.
A conventional front suspension for a steer axle includes a spring disposed on each side of the vehicle. The springs extends vertically between the vehicle frame and spring seats formed on the axle (e.g., by a plate welded or bolted to the axle beam). The springs abuts the frame and the axle beam at a lateral spacing approximately equal to the spacing between the longitudinal frame rails of the vehicle frame. This conventional suspension suffers from a significant drawback. In particular, the narrow spacing between the springs limits the roll stiffness that can be imparted by the suspension. Further, the narrow spacing induces a high vertical bending moment into the axle beam. As a result, the vehicle requires a relatively heavy and expensive axle beam to absorb the load.
The inventors herein have recognized a need for a suspension for coupling a steer axle assembly to a vehicle frame that will minimize and/or eliminate one or more of the above-identified deficiencies.